Biology subjects

Feng Earley, Y.

Publications and source records attributed to Feng Earley, Y..

6 recordsLinked to original sources

bioRxiv2026

Ryanodine receptor cluster remodeling links COL4A2 mutation to cerebral artery dysfunction

Pathogenic variants of COL4A1 and COL4A2, which encode the 1 and 2 chains of type IV collagen in vascular basement membranes, cause cerebral small vessel disease and intracerebral hemorrhage, but the signaling mechanisms that precede vascular damage remain incompletely defined. Here, we investigated cerebral arterial function in mice heterozygous for the Col4a2+/G646D mutation. Cerebral pial arteries from aged (12-month-old), but not young (3-month-old), Col4a2+/G646D mice exhibited impaired pressure-induced myogenic tone, whereas downstream parenchymal arterioles retained normal myogenic responsiveness, revealing a segment-selective vascular defect. The frequency of subcellular Ca2+ signals (Ca2+ sparks) generated by the release of Ca2+ through ryanodine receptors (RyR2s) on the sarcoplasmic reticulum (SR) was increased, and large-conductance Ca2+-activated K+ (BK) channel activity was elevated, in cerebral pial artery smooth muscle cells (SMCs) from aged Col4a2+/G646D mice. SR Ca2+ store load and Ryr2 transcript abundance were unchanged in these cells, but Stimulated Emission Depletion super-resolution microscopy revealed that RyR2 protein clusters were enlarged compared with controls. Protein kinase A (PKA) activation reproduced RyR2 cluster enlargement, whereas PKA inhibition normalized RyR2 cluster organization and BK channel activity in SMCs from aged Col4a2+/G646D mice. These findings identify age-associated, PKA-dependent, nanoscale remodeling of RyR2 clusters as a previously unknown mechanism underlying cerebral arterial dysfunction in COL4A2-related disease.

physiology↗

bioRxiv2026

TRPM4 Couples Mechanical Force to Myogenic Constriction Throughout the Resistance Vasculature

BackgroundMyogenic tone is a fundamental property of resistance arteries that stabilizes tissue perfusion by coupling intraluminal pressure to smooth muscle cell (SMC) depolarization, Ca2+ influx, and vasoconstriction. TRPM4 (transient receptor potential melastatin 4) cation channels are required for this response in cerebral arteries, but whether TRPM4-dependent mechanotransduction is conserved across the broader resistance vasculature has remained unknown. MethodsWe combined droplet digital PCR, a newly generated Trpm4-Cre transgenic reporter mouse line, native-cell patch-clamp electrophysiology, pressure myography, selective pharmacological inhibition, and novel SMC-specific Trpm4-knockout (Trpm4-smKO) mice to define the expression, regulation, and functional importance of TRPM4 in cerebral, mesenteric, and skeletal muscle resistance arteries. ResultsTrpm4 transcripts were detected in all three vascular beds, and genetic reporter-based mapping localized TRPM4 expression to SMCs in multiple organs. Using conventional whole-cell patch-clamp electrophysiology, we recorded cation currents activated by high intracellular [Ca2+] and sensitive to the selective TRPM4 blocker 4-chloro-2-(1-naphthyloxyacetamido) benzoic acid (NBA) in native SMCs from all three beds. In cells patch-clamped using the amphotericin B-perforated configuration, stretching the plasma membrane by applying negative pressure (-20 mmHg) through the patch pipette activated transient inward cation currents that were suppressed by NBA. The selective angiotensin II type 1 receptor (AT1R) blocker losartan also inhibited stretch-induced currents without affecting Ca2+-activated whole-cell TRPM4 currents, indicating that AT1R signaling is required for mechanotransduction in SMCs from all three vascular beds. In pressurized arteries with established myogenic tone, NBA produced reversible, concentration-dependent suppression of pressure-induced constriction of cerebral, mesenteric, and skeletal muscle arteries while sparing constriction induced by direct depolarization of SMCs with high (60 mM) extracellular [K+]. TRPM4-dependent whole-cell currents and stretch-induced cation currents were decreased in SMCs from Trpm4-smKO mice, and myogenic tone was essentially absent in all three vascular beds from these animals. ConclusionsThese findings show that TRPM4 is essential for pressure-induced SMC depolarization and myogenic constriction in the resistance vasculature.

physiology↗

bioRxiv2025

Elevated Na+/K+ Ratio in Alzheimers Disease: A Potential Biomarker for Braak Stage

Alzheimers disease (AD) is a neurodegenerative disorder characterized by cognitive decline, synaptic dysfunction, and the accumulation of amyloid plaques and neurofibrillary tangles. While prior research has focused mainly on protein aggregation and neuroinflammation, emerging evidence suggests that ionic imbalances, particularly involving sodium (Na+) and potassium (K+), may contribute to AD progression. Na+ and K+ are critical for maintaining neuronal membrane potential, regulating action potential firing, and supporting neurotransmitter function. Although studies primarily focused on absolute Na+ concentrations, the Na+/K+ ratio may provide a more sensitive marker of ionic dysregulation. Given that the Na+/K+ gradient is actively maintained by the Na/K-ATPase pump, a target known to be vulnerable in AD, we hypothesized that the Na+/K+ ratio is altered in AD. We analyzed postmortem tissue from the prefrontal cortex, thalamus, and cerebrospinal fluid (CSF) of 97 human subjects (67 AD, 30 controls). AD cases exhibited a significant increase in the Na+/K+ ratio in the thalamus and CSF, driven primarily by elevated Na+ levels. The Na+/K+ ratio positively correlated with Braak tangle stage, suggesting an association with AD progression. These findings provide novel insights into ionic dysregulation in AD and suggest that the CSF Na+/K+ ratio may serve as a valuable biomarker of disease severity and progression. Future research should explore the potential of targeting ionic homeostasis as a therapeutic strategy in AD.

biochemistry↗

bioRxiv2025

Cellular and Molecular Architecture of Renin-Angiotensin System Signaling in the PVN Under Cardiometabolic Stress

The hypothalamic paraventricular nucleus (PVN) integrates neuroendocrine and autonomic signals that regulate blood pressure and metabolism. Although the renin- angiotensin system (RAS) is implicated in neurogenic hypertension and obesity, cell-type- specific expression and regulation of its components within the PVN remain poorly understood. Here, we employed single-nucleus RNA sequencing (snRNA-seq) to profile the transcriptomic landscape of the PVN in male mice under baseline conditions and in models of DOCA-salt-induced hypertension and high-fat diet (HFD)-induced obesity. We identified major PVN cell types, including neurons, astrocytes, precursor oligodendrocytes, oligodendrocytes, microglia and endothelial cells, and further resolved eight transcriptionally distinct neuronal subtypes. Expression of RAS-related genes was highly cell-type specific: Agt (angiotensinogen) was enriched in astrocytes, whereas Ace (angiotensin-converting enzyme), Atp6ap2 (also known as the (pro)renin receptor [PRR]), Agtr1a (angiotensin II type 1a receptor, aka AT1aR), Lnpep (leucyl/cystinyl aminopeptidase, aka angiotensin 4 receptor [AT4R]), and the Mas1 proto-oncogene were predominantly expressed in neurons. DOCA-salt treatment increased the proportion of GABAergic and vasopressin neurons and enhanced neuronal Agt and Atp6ap2 expression, while reducing astrocytic Agt, suggesting activation of a vasoconstrictive RAS axis. HFD exposure increased excitatory and stress-responsive neuronal subtypes (glutamatergic, vasopressin, corticotropin-releasing hormone) and upregulated Atp6ap2, Agtr1b, Lnpep, and Mas1 in vasopressin neurons, while downregulating multiple RAS genes in GABAergic neurons. These findings reveal dynamic, cell-type-specific remodeling of RAS signaling in the PVN in response to hypertensive and metabolic stress, providing a transcriptomic atlas of RAS expression in the PVN and identifying potential cellular targets for therapeutic strategies addressing cardiometabolic disorders.

genomics↗

bioRxiv2022

(Pro)Renin Receptor Antagonism Attenuates High-Fat-Die-Induced Hepatic Steatosis in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) comprises a spectrum of liver damage directly related to diabetes, obesity, and metabolic syndrome. The (pro)renin receptor (PRR) has recently been demonstrated to play a role in glucose and lipid metabolism. Here, we hypothesized that inhibition of the PRR would prevent the development of diet-induced hepatic steatosis and fibrosis. To test our hypothesis, we fed wild-type mice on a C57Bl/6J background either a high-fat diet (HFD; 60% calories from fat) or normal fat diet (NFD; 10% calories from fat) with matching calories for 6 weeks. An 8-week methionine choline-deficient (MCD) diet was used to induce fibrosis in C57BL/6J mice. Two weeks following diet treatment, mice were implanted with a subcutaneous osmotic pump delivering either PRO20, a peptide PRR antagonist, or scrambled peptide (700 g/kg/d) for 4 or 6 weeks. We found that a 6-week HFD significantly increased liver lipid accumulation, as detected by Oil Red O staining, and liver triglyceride content compared with NFD-fed mice. Importantly, PRO20 treatment significantly reduced hepatic lipid accumulation in HFD-fed mice without affecting body weight or glucose levels. Furthermore, PRR antagonism attenuated HFD-induced steatosis, particularly microvesicular steatosis. In the MCD diet model, the percentage of collagen area detected by Sirius Red staining was reduced in PRO20-treated compared with control mice. PRO20 treatment also significantly decreased levels of liver alanine aminotransferase (ALT), an indicator of liver damage, in MCD-fed mice compared with controls. Mechanistically, we found that PRR antagonism prevented HFD-induced increases in PPAR{gamma} and glycerol-3-phosphate acyltransferase 3 expression in the liver. Taken together, our findings establish the mechanism by which PRR regulates lipid metabolism in the liver and suggest the therapeutic potential of PRR antagonism for the treatment of liver steatosis and fibrosis development in NAFLD.

pathology↗

bioRxiv2020

Evidence for unique small RNA modifications in Alzheimers disease

BackgroundWhile significant advances have been made in uncovering the aetiology of Alzheimers disease and related dementias at the genetic level, molecular events at the epigenetic level remain largely undefined. Emerging evidence indicates that small non-coding RNAs (sncRNAs) and their associated RNA modifications are important regulators of complex physiological and pathological processes, including aging, stress responses, and epigenetic inheritance. However, whether small RNAs and their modifications are altered in dementia is not known. MethodsWe performed LC-MS/MS-based, high-throughput assays of small RNA modifications in post-mortem samples of the prefrontal lobe cortices of Alzheimers disease (AD) and control individuals. We noted that some of the AD patients has co-occurring vascular cognitive impairment-related pathology (VaD). FindingsWe report altered small RNA modifications in AD samples compared with normal controls. The 15-25-nucleotide (nt) RNA fraction of these samples was enriched for microRNAs, whereas the 30-40-nt RNA fraction was enriched for tRNA-derived small RNAs (tsRNAs), rRNA-derived small RNAs (rsRNAs), and YRNA-derived small RNAs (ysRNAs). Interestingly, most of these altered RNA modifications were detected both in the AD and AD with co-occurring vascular dementia subjects. In addition, sequencing of small RNA in the 30-40-nt fraction from AD cortices revealed reductions in rsRNA-5S, tsRNA-Tyr, and tsRNA-Arg. InterpretationThese data suggest that sncRNAs and their associated modifications are novel signals that may be linked to the pathogenesis and development of Alzheimers disease. FundingNIH grants (R01HL122770, R01HL091905, 1P20GM130459, R01HD092431, P50HD098593, GM103440), AHA grant (17IRG33370128), Sigmund Gestetner Foundation Fellowship to P Kehoe. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSAlzheimers disease (AD) and vascular dementia (VaD) are marked by cognitive impairment and neuropathologies caused by significant neuronal death. Associated gene mutations are rare in subjects with dementia, and the aetiology of these diseases is still not completely understood. Recent emerging evidence suggests that epigenetic changes are risk factors for the development of dementia. However, studies assessing small RNA modifications--one of the features of epigenetics--in dementia are lacking. Added value of this studyWe used high-throughput liquid chromatography-tandem mass spectrometry and small RNA sequencing to profile small RNA modifications and the composition of small RNAs in post-mortem samples of the prefrontal cortex of AD and control subjects. We detected and quantified 16 types of RNA modifications and identified distinct small non-coding RNAs and modification signatures in AD subjects compared with controls. Implications of all the available evidenceThis study identified novel types and compositions of small RNA modifications in the prefrontal cortex of AD patients compared with control subjects in post-mortem samples. The cellular locations of these RNA modifications and whether they are drivers or outcomes of AD are still not known. However, results from the present study may open new possibilities for dissecting the dementia pathology.

cell biology↗